Malicious PDF — malware analysis report

Static analysis result for SHA-256 b851f9bbb08eae78…

MALICIOUS

PDF

76.6 KB Created: 2021-09-19 04:56:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 15173e050801457caa7ded966184c05f SHA-1: b010edde33beb72705ba9c580bbaa1a947bce497 SHA-256: b851f9bbb08eae7836354700bc9acc6018bfc356fcdfb5798c62ba8f2dd90a26
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ML classifiers and ClamAV as malicious, exhibiting characteristics of a link farm with numerous external URIs pointing to disposable domains. The document body is heavily obfuscated, preventing a clear understanding of its specific intent beyond serving as a distribution point for other potentially malicious files.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9901

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://rsst77.ru/upload/files/69185235233.pdf In PDF document text
    • http://boathousebrokerage.com/userfiles/file/8810220631.pdfIn PDF document text
    • https://bahia-group.com/ckfinder/userfiles/files/piburukavedeguk.pdfIn PDF document text
    • https://fnb-concepts.com/images/uploads/files/60913667418.pdfIn PDF document text
    • http://orlickachata.cz/files/files/79621854744.pdfIn PDF document text
    • https://samavetpharm.com/userfiles/files/fafomexotuko.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/1hvmu9i96oteg8hgp77n1cuoiv/nedavezatemefowogurusuxob.pdfIn PDF document text
    • https://skl.deindrukdemo.nl/upload/files/sirivapinomi.pdfIn PDF document text
    • http://namjapizza.com/app/webroot/files/41660081376.pdfIn PDF document text
    • http://acudrved.com/ckfinder/userfiles/files/1091813919.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161422413b73d1---11388420301.pdfIn PDF document text
    • http://7166867.ru/ckfinder/userfiles/files/34900357320.pdfIn PDF document text
    • http://zygzak.eu/foto_dane/wysiwyg/File/8576686583.pdfIn PDF document text
    • http://globalroomplus.com/bot/ckfinder/uf/files/logejotewewolokilutalor.pdfIn PDF document text
    • http://metallpress.ru/files/91242643877.pdfIn PDF document text
    • https://cmottaviproductive.it/uploads/file/81320113859.pdfIn PDF document text
    • http://ahkkpcm.org/userfiles/57523224313.pdfIn PDF document text
    • http://szentdorottyapatika.hu/files/52722181840.pdfIn PDF document text
    • http://swhos.com/upload/files/8149702569.pdfIn PDF document text
    • https://dacinsara.ro/fckfiles/file/xekalomapumexubufuderefil.pdfIn PDF document text
    • http://quocteanviet.com/img-chamthi/files/gavobatiga.pdfIn PDF document text
    • https://rumahbaruku.com/contents/files/xutubagujezipofanuwom.pdfIn PDF document text
    • http://vertracapital.com/uploads/files/mosidixem.pdfIn PDF document text
    • https://assofmt.org/ckfinder/userfiles/files/jogagodefuzevixonisab.pdfIn PDF document text
    • http://www.elmundodelapiscina.com/ckfinder/userfiles/files/82352425465.pdfIn PDF document text
    • http://ieltsadd.ir/cache/fck_files/file/dajawijututojalokum.pdfIn PDF document text
    • http://tnslib.tools/userfiles/files/36312741584.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=movie+shot+apkPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c938.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC938 17080 bytes
SHA-256: f9564f8e9600ec368631dbf3ffc0c977e947f7c236bc563dad2c9a602977fc4b
font_01_sfnt_off0000f580.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF580 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010d97.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D97 10248 bytes
SHA-256: 67684dcbae818b2bf68c5b5ec99675db2ee1e1cc4829b49adcd9f18a4ac3dea6